Computing devices can be communicatively coupled to one another via a computer network to facilitate the transmission of data (e.g., network packets) between the computing devices. Data can be sent between the networked computing devices according to various protocols, for example using a “layered” networking model. In some instances, streams of network traffic can be multiplexed within an application layer connection to promote efficiency by forgoing the need to establish separate application layer connections for each stream. However, the rate at which network traffic can be transmitted using such an approach may be limited due to congestion avoidance mechanisms used in many networking protocols. For example, this approach may result in a relatively slow increase in the size of a congestion window maintained by a computing device in the network, which leads to a relatively slow increase in the rate at which data can be sent in the network.